An autopsy is pending and further details were not immediately available.

Actresses Erin Moran, left, and Marion Ross pose together at the Academy of Television Arts and Sciences’ “A Father’s Day Salute to TV Dads” in the North Hollywood section of Los Angeles on Thu., June 18, 2009.
AP

“Happy Days,” a sitcom set in Milwaukee, was broadcast from 1974-1984. It also starred Ron Howard and Henry Winkler played Arthur “The Fonz” Fonzarelli.

Moran made guest appearances on series such as “Murder, She Wrote” and “The Love Boat.”

In this July 12, 2001 file photo, Garry Marshall, from left, Tom Bosley, Marion Ross, Erin Moran, Henry Winkler, and Anson Williams of the television show “Happy Days,” pose after Ross received a star on the Hollywood Walk of Fame in the Hollywood section of Los Angeles.
AP

Winkler took to Twitter late Saturday to express his condolences -- along with other celebrities.

OH Erin... now you will finally have the peace you wanted so badly here on earth ...Rest In It serenely now.. too soon